/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
using System;
using java = biz.ritter.javapi;

namespace org.apache.commons.codec.binary
{

    /**
     * Provides Base64 encoding and decoding in a streaming fashion (unlimited size). When encoding the default lineLength
     * is 76 characters and the default lineEnding is CRLF, but these can be overridden by using the appropriate
     * constructor.
     * <p>
     * The default behaviour of the Base64OutputStream is to ENCODE, whereas the default behaviour of the Base64InputStream
     * is to DECODE. But this behaviour can be overridden by using a different constructor.
     * </p>
     * <p>
     * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
     * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
     * </p>
     * <p>
     * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode
     * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
     * </p>
     * 
     * @author Apache Software Foundation
     * @version $Id: Base64OutputStream.java 799806 2009-08-01 04:33:17Z ggregory $
     * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
     * @since 1.4
     */
    public class Base64OutputStream : java.io.FilterOutputStream
    {
        private readonly bool doEncode;

        private readonly Base64 base64;

        private readonly byte[] singleByte = new byte[1];

        /**
         * Creates a Base64OutputStream such that all data written is Base64-encoded to the original provided OutputStream.
         * 
         * @param out
         *            OutputStream to wrap.
         */
        public Base64OutputStream(java.io.OutputStream outJ)
        :
            this(outJ, true){
        }

        /**
         * Creates a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the
         * original provided OutputStream.
         * 
         * @param out
         *            OutputStream to wrap.
         * @param doEncode
         *            true if we should encode all data written to us, false if we should decode.
         */
        public Base64OutputStream(java.io.OutputStream outJ, bool doEncode) :
            base(outJ)
        {
            this.doEncode = doEncode;
            this.base64 = new Base64();
        }

        /**
         * Creates a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the
         * original provided OutputStream.
         * 
         * @param out
         *            OutputStream to wrap.
         * @param doEncode
         *            true if we should encode all data written to us, false if we should decode.
         * @param lineLength
         *            If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to
         *            nearest multiple of 4). If lineLength <=0, the encoded data is not divided into lines. If doEncode is
         *            false, lineLength is ignored.
         * @param lineSeparator
         *            If doEncode is true, each line of encoded data will be terminated with this byte sequence (e.g. \r\n).
         *            If lineLength <= 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
         */
        public Base64OutputStream(java.io.OutputStream outJ, bool doEncode, int lineLength, byte[] lineSeparator) :
            base(outJ)
        {
            this.doEncode = doEncode;
            this.base64 = new Base64(lineLength, lineSeparator);
        }

        /**
         * Writes the specified <code>byte</code> to this output stream.
         * 
         * @param i
         *            source byte
         * @throws IOException
         *             if an I/O error occurs.
         */
        public void write(int i)
        {//throws IOException {
            singleByte[0] = (byte)i;
            write(singleByte, 0, 1);
        }

        /**
         * Writes <code>len</code> bytes from the specified <code>b</code> array starting at <code>offset</code> to this
         * output stream.
         * 
         * @param b
         *            source byte array
         * @param offset
         *            where to start reading the bytes
         * @param len
         *            maximum number of bytes to write
         * 
         * @throws IOException
         *             if an I/O error occurs.
         * @throws NullPointerException
         *             if the byte array parameter is null
         * @throws IndexOutOfBoundsException
         *             if offset, len or buffer size are invalid
         */
        public void write(byte[] b, int offset, int len)
        {//throws IOException {
            if (b == null)
            {
                throw new java.lang.NullPointerException();
            }
            else if (offset < 0 || len < 0)
            {
                throw new java.lang.IndexOutOfBoundsException();
            }
            else if (offset > b.Length || offset + len > b.Length)
            {
                throw new java.lang.IndexOutOfBoundsException();
            }
            else if (len > 0)
            {
                if (doEncode)
                {
                    base64.encode(b, offset, len);
                }
                else
                {
                    base64.decode(b, offset, len);
                }
                flush(false);
            }
        }

        /**
         * Flushes this output stream and forces any buffered output bytes to be written out to the stream. If propogate is
         * true, the wrapped stream will also be flushed.
         * 
         * @param propogate
         *            boolean flag to indicate whether the wrapped OutputStream should also be flushed.
         * @throws IOException
         *             if an I/O error occurs.
         */
        private void flush(bool propogate)
        {//throws IOException {
            int avail = base64.avail();
            if (avail > 0)
            {
                byte[] buf = new byte[avail];
                int c = base64.readResults(buf, 0, avail);
                if (c > 0)
                {
                    outJ.write(buf, 0, c);
                }
            }
            if (propogate)
            {
                outJ.flush();
            }
        }

        /**
         * Flushes this output stream and forces any buffered output bytes to be written out to the stream.
         * 
         * @throws IOException
         *             if an I/O error occurs.
         */
        public void flush()
        {//throws IOException {
            flush(true);
        }

        /**
         * Closes this output stream and releases any system resources associated with the stream.
         * 
         * @throws IOException
         *             if an I/O error occurs.
         */
        public void close()
        {//throws IOException {
            // Notify encoder of EOF (-1).
            if (doEncode)
            {
                base64.encode(singleByte, 0, -1);
            }
            else
            {
                base64.decode(singleByte, 0, -1);
            }
            flush();
            outJ.close();
        }

    }
}